subsonic wind-tunnel wall corrections on a wing with a clark y-14 airfoil

222 Pages·2011·5.19 MB·English

by  Tommy Blackwell

SUBSONIC WIND-TUNNEL WALL CORRECTIONS ON A WING WITH A
CLARK Y-14 AIRFOIL

A Masters Project
Presented to
The Faculty of the Department of
Mechanical and Aerospace Engineering
San Jose State University

In Partial Fulfillment
Of the Requirements for a Degree
Master of Science
In
Aerospace Engineering

By
Tommy James Blackwell
May 2011
© 2011
Tommy James Blackwell
ALL RIGHTS RESERVED

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ABSTRACT
As our civilization relies more heavily on aircrafts and rockets, the use of wind-tunnels has
increasing been integrated as an important aeronautical tool in their design. Even though wind-
tunnels are great scientific tools, they do have their flaws. Based on the specific wind-tunnel
design, one of the main negatives is that wind-tunnels cannot simulate free-flight conditions
without having to correct the data for wall effects and other flow phenomena.
Both two and three-dimensional flows need to have corrections applied that are unique to that
wind-tunnels design. For two dimensional flows, corrections that can be obtain are for the
(cid:959)(cid:2009)(cid:481)(cid:3)(cid:959)(cid:1855) (cid:481)(cid:3)(cid:1853)(cid:1866)(cid:1856)(cid:3)(cid:959)(cid:1855) with direct corrections available for (cid:25)(cid:481)(cid:3)(cid:147)(cid:481)(cid:3)(cid:21)(cid:135)(cid:481)(cid:2009)(cid:481)(cid:3)(cid:1855) (cid:481)(cid:3)(cid:1853)(cid:1866)(cid:1856)(cid:3)(cid:1855) . The
(cid:3039) (cid:3040)(cid:3117) (cid:3039) (cid:3040)(cid:3117)
(cid:3120) (cid:3120)
corrections are developed from the buoyancy, solid and wake blockages, and streamline
curvature corrections. For tree-dimensional flows, corrections can be obtain are (cid:959)(cid:2009)(cid:481)(cid:3)(cid:959)(cid:1855) (cid:481)(cid:3)(cid:959)(cid:1855) ,
(cid:3039) (cid:3040)(cid:3117)
(cid:3120)
(cid:959)(cid:2009) (cid:3)(cid:1853)(cid:1866)(cid:1856)(cid:3)(cid:959)(cid:1829) (cid:484) These corrections depend on the methods applied to the two-dimensional cases
(cid:3036) (cid:3005)(cid:3036)
along with the method of images.
The experiments contained in this project are utilizing an AEROLAB wind-tunnel along with a
ClarkY-14 airfoil and wing. The wind-tunnel was set up to have inlet velocities of 6, 30, 68 and
102 mph and outlet atmospheric environmental conditions. The data collected with the correction
factors applied was then compared with free-flight CFD models to compare corrections
effectiveness

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ACKNOWLEDGEMENTS

I would like to take the opportunity to thank Dr. Mourtos and Dr. Papadopoulos for their support
throughout this project. Their assistance has been invaluable during the process of finishing this
project. I would also like to thank San Jose State University for the use of their wind tunnel
facility.

A special thanks goes to my mom, dad and family, who have stood by me with encouragement
and moral support. Also to my Aunt Helen and Jim Lyons, who provided editing assistance, I
thank you so much for your time and effort.

Finally, I thank Hai Le, Albert Rios and Paul Linggi for being a sounding board and
encouragement throughout the project.

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Table of Contents
List of Figures ................................................................................................................................. 1(cid:3)
List of Variables .............................................................................................................................. 6(cid:3)
Chapter 1: Introduction ................................................................................................................. 11(cid:3)
1.1 Background ......................................................................................................................... 11(cid:3)
1.1.1 Development of Wind-Tunnels .................................................................................... 11(cid:3)
1.1.2 Wind-Tunnel Design .................................................................................................... 13(cid:3)
1.1.3 Wall Effects ................................................................................................................. 16(cid:3)
1.1.4 Wall Effect Corrections ............................................................................................... 19(cid:3)
A. The Method of Images ..................................................................................................... 19(cid:3)
Chapter 2: Clark Y-14 Airfoil and Wing ...................................................................................... 24(cid:3)
2.1 Development of Airfoils and Wings ................................................................................... 24(cid:3)
2.2 Development of the Clark Y-14 .......................................................................................... 27(cid:3)
2.3 Characterizing the Clark Y-14 ............................................................................................ 28(cid:3)
2.3.1 Aerodynamic Forces .................................................................................................... 29(cid:3)
2.3.2 Low-Speed Aerodynamics ........................................................................................... 30(cid:3)
2.3.3 Characterizing Airfoil Performance ............................................................................. 31(cid:3)
2.3.4 Characterizing Wing Performance ............................................................................... 32(cid:3)
2.4 Obtaining Airfoil Characteristics from Data ....................................................................... 32(cid:3)
2.4.1 Airfoil control Volume Analysis ................................................................................. 32(cid:3)
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2.4.2 Test Section Control Volume Analysis........................................................................ 33(cid:3)
2.4.3 Wing Direct Force Measurement ................................................................................. 34(cid:3)
Chapter 3: AEROLAB Low-Speed Wind Tunnel ........................................................................ 36(cid:3)
3.1 General AEROLAB Wind Tunnel Specifications .............................................................. 36(cid:3)
3.2 Test Section and Instrumentation ........................................................................................ 37(cid:3)
3.3 Clark Y-14 Airfoil and Wing Models ................................................................................. 39(cid:3)
Chapter 4: Two-Dimensional Wall Corrections for the Clark Y-14 Airfoil ................................ 40(cid:3)
4.1 Buoyancy Correction .......................................................................................................... 40(cid:3)
4.1.1 Theory .......................................................................................................................... 40(cid:3)
4.1.2 Approach ...................................................................................................................... 42(cid:3)
4.1.3 Results .......................................................................................................................... 49(cid:3)
4.1.4 Discussion .................................................................................................................... 51(cid:3)
4.2 Solid Blockage Correction .................................................................................................. 52(cid:3)
4.2.1 Theory .......................................................................................................................... 52(cid:3)
4.2.2 Approach ...................................................................................................................... 53(cid:3)
4.2.3 Results .......................................................................................................................... 55(cid:3)
4.2.4 Discussion .................................................................................................................... 57(cid:3)
4.3 Wake Blockage Correction ................................................................................................. 58(cid:3)
4.3.1 Theory .......................................................................................................................... 58(cid:3)
4.3.2 Approach ...................................................................................................................... 59(cid:3)
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4.3.3 Results .......................................................................................................................... 61(cid:3)
4.3.4 Discussion .................................................................................................................... 66(cid:3)
4.4 Streamline Curvature Correction ........................................................................................ 67(cid:3)
4.4.1 Theory .......................................................................................................................... 67(cid:3)
4.4.2 Approach ...................................................................................................................... 69(cid:3)
4.4.3 Results .......................................................................................................................... 71(cid:3)
4.4.4 Discussion .................................................................................................................... 75(cid:3)
Chapter 5: Three-Dimensional Wall Corrections for the Clark Y-14 Wing ................................ 77(cid:3)
5.1 Buoyancy Correction .......................................................................................................... 77(cid:3)
5.1.1 Theory .......................................................................................................................... 77(cid:3)
5.1.2 Approach ...................................................................................................................... 78(cid:3)
5.1.3 Results .......................................................................................................................... 78(cid:3)
5.1.4 Discussion .................................................................................................................... 79(cid:3)
5.2 Solid Blockage Correction .................................................................................................. 79(cid:3)
5.2.1 Theory .......................................................................................................................... 79(cid:3)
5.2.3 Results .......................................................................................................................... 80(cid:3)
5.2.4 Discussion .................................................................................................................... 81(cid:3)
5.3 Wake Blockage Correction ................................................................................................. 82(cid:3)
5.3.1 Theory .......................................................................................................................... 82(cid:3)
5.3.2 Approach ...................................................................................................................... 82(cid:3)
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5.3.3 Results .......................................................................................................................... 84(cid:3)
5.3.4 Discussion .................................................................................................................... 85(cid:3)
5.4 Method of Images ............................................................................................................... 85(cid:3)
5.4.1 Theory .......................................................................................................................... 85(cid:3)
5.4.2 Approach ...................................................................................................................... 89(cid:3)
5.4.3 Results .......................................................................................................................... 91(cid:3)
5.4.4 Discussion .................................................................................................................... 92(cid:3)
5.5 Streamline Curvature Correction ........................................................................................ 93(cid:3)
5.5.1 Theory .......................................................................................................................... 93(cid:3)
5.5.2 Approach ...................................................................................................................... 93(cid:3)
5.5.3 Results .......................................................................................................................... 94(cid:3)
Chapter 6: Computational Fluid Dynamics of the Clark Y-14 Airfoil ........................................ 98(cid:3)
6.1 Grids .................................................................................................................................... 98(cid:3)
6.2 Setup ................................................................................................................................. 100(cid:3)
6.3 Results ............................................................................................................................... 101(cid:3)
6.4 Discussion ......................................................................................................................... 111(cid:3)
Chapter 7: Conclusion................................................................................................................ 112(cid:3)
Works Cited ................................................................................................................................ 113(cid:3)
Appendix A ................................................................................................................................. 115(cid:3)
Appendix B ..................................................................................................................................... 1(cid:3)
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2D Airfoil Data (Pressure) .......................................................................................................... 1(cid:3)
2D Airfoil Calculations ............................................................................................................. 59(cid:3)
Appendix C ................................................................................................................................... 71(cid:3)
3D Wing Data ........................................................................................................................... 71(cid:3)
3D Wing Calculations ............................................................................................................... 89(cid:3)

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